What is the endosperm formed by?

Endosperm is a triploid parenchymal tissue. Its cells are saturated with nutrients. The endosperm tissue is formed by cells of a round or angular shape, and the walls are thin or thick. Closer to the center, the cells are larger than along the periphery. At the developmental stage in the cells of the endosperm, the following are observed: the nucleus, cytoplasm, plastids, and in the mature cell – filling with nutrients (starch, semi-fiber, sugar, proteins, oils), and the nucleus decreases or completely dissolves. In cereals, starch is absolutely absent in the cells.